Method for making light emitting diode chip

Abstract

A method for making a light emitting diode chip includes following steps: providing a sapphire substrate, the sapphire substrate having a plurality of protrusions on an upper surface thereof; forming an un-doped GaN layer on the upper surface of the sapphire substrate, the un-doped GaN layer partly covering the protrusions to expose a part of each of the protrusions; etching the un-doped GaN layer to expose a top end of each of the protrusions; and forming an n-type GaN layer, an active layer, and a p-type GaN layer sequentially on the top ends of the protrusions and the un-doped GaN layer.

What is claimed is: 
     
         1 . A method for making a light emitting diode chip, comprising:
 providing a sapphire substrate, the sapphire substrate having a plurality of protrusions on an upper surface thereof;   forming an un-doped GaN layer on the upper surface of the sapphire substrate, the un-doped GaN layer partly covering the protrusions to expose a part of each of the protrusions;   etching the un-doped GaN layer to expose a top end of each of the protrusions; and   forming an n-type GaN layer, an active layer, and a p-type GaN layer sequentially on the top ends of the protrusions and the un-doped GaN layer.   
     
     
         2 . The method of  claim 1 , wherein the un-doped GaN layer is etched by dry etching or wet etching. 
     
     
         3 . The method of  claim 2 , wherein the un-doped GaN layer is etched by inductively coupled plasma etching. 
     
     
         4 . The method of  claim 1 , wherein the active layer is a multiple quantum well layer. 
     
     
         5 . The method of  claim 1 , wherein the protrusions each have a semi-circular, triangular or trapezoid cross section. 
     
     
         6 . The method of  claim 1 , wherein the un-doped GaN layer comprises a first portion and a second portion, the first portion is located between two adjacent protrusions, the second portion is located on the top ends of the protrusions, and the second portion of the un-doped GaN layer is totally etched away after the etching of the un-doped GaN layer. 
     
     
         7 . The method of  claim 1 , wherein before forming the n-type GaN layer on the top ends of the protrusions and the un-doped GaN layer, an additional un-doped GaN layer is formed on the top ends of the protrusions and the un-doped GaN layer, and then the n-type GaN layer, the active layer, and the p-type GaN layer are sequentially formed on the additional un-doped GaN layer. 
     
     
         8 . A method for making a light emitting diode chip, comprising:
 providing a sapphire substrate, the sapphire substrate having a plurality of protrusions on an upper surface thereof;   forming an un-doped GaN layer on the upper surface of the sapphire substrate until the un-doped GaN layer totally covering the protrusions;   etching the un-doped GaN layer to expose a top end of each of the protrusions; and   forming an n-type GaN layer, an active layer, and a p-type GaN layer sequentially on the top ends of the protrusions and the un-doped GaN layer.   
     
     
         9 . The method of  claim 8 , wherein the un-doped GaN layer is etched by dry etching or wet etching. 
     
     
         10 . The method of  claim 9 , wherein the un-doped GaN layer is etched by inductively coupled plasma etching. 
     
     
         11 . The method of  claim 8 , wherein the active layer is a multiple quantum well layer. 
     
     
         12 . The method of  claim 8 , wherein the protrusions each have a semi-circular, triangular or trapezoid cross section. 
     
     
         13 . The method of  claim 8 , wherein the un-doped GaN layer comprises a first portion and a second portion, the first portion is located between two adjacent protrusions, the second portion is located on the upper end of each of the protrusions, the second portion of the un-doped GaN layer is totally etched away after the etching of the un-doped GaN layer. 
     
     
         14 . The method of  claim 8 , wherein before forming the n-type GaN layer on the top ends of the protrusions and the un-doped GaN layer, a second un-doped GaN layer is formed on the top ends of the protrusions, then the n-type GaN layer, the active layer, and the p-type GaN layer are sequentially formed on the second un-doped GaN layer.